2,357 research outputs found

    Super-spreading Events and Contribution to Transmission of MERS, SARS, and COVID-19

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    There is no clear definition for the term ‘super-spreader’ or ‘super-spreading event’. The World Health Organization refers to a super-spreader as a patient (or an event) that may transmit infection to a larger number of individuals than is usual by one individual (or event). In the severe acute respiratory syndrome (SARS) situation, a super-spreading event was defined as the transmission of SARS to at ≥8 contacts, and other authors defined this as individuals infecting an unusually large number of secondary cases [ 1 , 2 ]. A super-spreading event could merely be defined as an event in which one patient infects far more people than an average patient does, which is estimated by the basic reproduction number (R0)

    ALMA 690 GHz observations of IRAS 16293-2422B: Infall in a highly optically-thick disk

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    We present sensitive, high angular resolution (\sim 0.2 arcsec) submillimeter continuum and line observations of IRAS 16293-2422B made with the Atacama Large Millimeter/Submillimeter Array (ALMA). The 0.45 mm continuum observations reveal a single and very compact source associated with IRAS 16293-2422B. This submillimeter source has a deconvolved angular size of about 400 {\it milli-arcseconds} (50 AU), and does not show any inner structure inside of this diameter. The H13^{13}CN, HC15^{15}N, and CH3_{3}OH line emission regions are about twice as large as the continuum emission and reveal a pronounced inner depression or "hole" with a size comparable to that estimated for the submillimeter continuum. We suggest that the presence of this inner depression and the fact that we do not see inner structure (or a flat structure) in the continuum is produced by very optically thick dust located in the innermost parts of IRAS 16293-2422B. All three lines also show pronounced inverse P-Cygni profiles with infall and dispersion velocities larger than those recently reported from observations at lower frequencies, suggesting that we are detecting faster, and more turbulent gas located closer to the central object. Finally, we report a small east-west velocity gradient in IRAS 16293-2422B that suggests that its disk plane is likely located very close to the plane of the sky.Comment: Accepted to ApJ

    Fijación activa y perforación ventricular: ¿una nueva entidad?

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    First, a new active fixation lead was implanted in the interventricular septum; the old lead was then extracted with a Cook stylet. The patient’s clinical course was satisfactory and there were no procedure-related complications. In conclusion, within the battery of diagnostic tests available to investigate suspected cardiac perforation, computed angiotomography of the chest is a highly useful complementary technique for the management of this complication

    Web 2.0 en el proceso de enseñanza-aprendizaje. Aplicación a la enseñanza de Economía de la Empresa

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    El uso de Internet y su evolución acelerada en el tiempo no afecta exclusivamente a las empresas, sino que su ritmo viene marcado precisamente por los que se han de considerar nuevos productores de contenido en la Red. La Universidad no puede quedarse atrás en el uso de las TIC pero tampoco puede centrarse exclusivamente en plataformas de aprendizaje on-line de sofisticación elevada –OCW, Moodle, entre otros-, pero sin otorgar poder para modificar y generar contenidos a los usuarios. La Unidad Docente de Organización de Empresas del Departamento de Economía y Gestión Forestal de la Escuela Técnica Superior de Ingenieros de Montes de la Universidad Politécnica de Madrid propone el uso de plataformas Web 2.0 con el objeto de desarrollar competencias tradicionales y competencias 2.0. Estas plataformas tienen una gran acogida entre el alumnado, presentan utilidad tanto en el presente como en el futuro, y se puede utilizar como plataforma de Learning 2.0 de la Economía y Organización de Empresa

    Control of a multi-axis platform for metrological purposes using diferential flatness

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    Positioning and tracking devices with micrometer range and sub-micrometer resolution are becoming of special interest in recent years for an extending range of applications including metrological devices, manipulators and mechanization systems both in research and high precision industries (for example, semiconductors). The control of these systems is not an easy task because of its normally high stiffness and the coupling existing between the different degrees of freedom. The present work proposes a control strategy based on differential flatness for static positioning and dynamic trajectory tracking with a platform of three degrees of freedom. The system uses piezoelectric actuators and is specially conceived for metrological devices, which do not suffer important external loads. The proposed method permits to decouple the design of a closed loop control for each degree of freedom and calculates an open loop command directly from the trajectory definition in the three degrees of freedom. The performance of the controller has been experimentally checked both in positioning and tracking applications

    Identification and Validation of Novel Drug Targets for the Treatment of Plasmodium falciparum Malaria: New Insights

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    In order to counter the malarial parasite’s striking ability to rapidly develop drug resistance, a constant supply of novel antimalarial drugs and potential drug targets must be available. The so-called Harlow-Knapp effect, or “searching under the lamp post,” in which scientists tend to further explore only the areas that are already well illuminated, significantly limits the availability of novel drugs and drug targets. This chapter summarizes the pool of electron transport chain (ETC) and carbon metabolism antimalarial targets that have been “under the lamp post” in recent years, as well as suggest a promising new avenue for the validation of novel drug targets. The interplay between the pathways crucial for the parasite, such as pyrimidine biosynthesis, aspartate metabolism, and mitochondrial tricarboxylic acid (TCA) cycle, is described in order to create a “road map” of novel antimalarial avenues

    Vaccination of children against COVID-19: the experience in Latin America

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    The Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread globally, becoming a long-lasting pandemic [1,2,3]. As is so often the case for infectious diseases, vulnerable communities are likely to demonstrate the worse effects and this holds true for COVID-19 in Latin America [4]. Early in the pandemic, it was believed that COVID-19 did not significantly affect children. However, since the first confirmed pediatric case of COVID-19 was reported in Shenzhen, China, many cases have been reported and studied in pediatric patients [5]. It is now known that COVID-19 can affect children of all ages [6,7,8,9]. Although in many settings children usually have a lower risk of exposure and are tested less frequently than adults, the incidence in some countries in children is similar to that in adults [10]
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